Steam drier



Nov. 18, 1941.

R. c. ROE

STEAM DRIER Filed Nov. 22, 1939 2 Sheets-Sheet l y 2,262',s6o

R. C. ROE

.STEAM DRIER Nov. '18, 1941;

Filed Nov. 22, 1939 2 Sheets-Sheet 2 Patented Nov. 18, 1 941 STEAM DRIERRalph C.` Roe, Englewood, N. J., assignor of onelalf to Stephen W.Borden, Summit, N. J.

Application November 22, 1939, Serial No. 305,(506

9 Claims.

This invention of improvements in apparatus for the drying of air andgases, or the separation of liquids from gases, has relation inparticular to apparatus for separating water from steam, and the term"steam drier" herein employed is intended to cover apparatus for any orall of the purposes mentioned.

The invention has relation to steam driers of the centrifugal type andhas for its object the provision of' improvements which shall enablecertain advantages to be obtained.

One object of the invention is to provide a steam drier in which thevelocity of the steam in the separating chamber is very greatlyincreased by converting some of the pressure energy of the steam intovelocity energy and thereby obtaining a more complete separation ofmoisture from the steam. Another object is to obtain a very greatlyincreased velocity but with a very simple type of Construction becausethe Simplicity of construction is highly desirable when amultiplicity'of such separators are combined into a single unit ashereinafter described.

A further object is to provide a drier of multiple construction Wherebya multiplicity of streams of steam, each stream containing a difiorentmoisture content, may be led through the multiple drier and each streamwill receive separate and independent drying treatment.

In the drawings, Figs. 1 and 2 illustrate a single drier, Fig. '1 beinga horizontal section on line l-l of Fig 2, and Fig 2 being a verticalsection on line 2-2 of Fig. 1. Fig. 3 is a similar section to Fig. 1:but showing a multiplicity of nozzles entering a single separationchamber. Figs. 4 and 5 illustrate a multiple type drier, Fig. 4 being ahorizontal section on line 4-4 of Fig. 5 and Fig. 5 being a Verticalsection on line 5-5 of Fig. 4. Fig. 6 is an enlarged view of portion 5of the drier.

Referring now to Figs. 1 and 2, l ls an outer casing in the form of acylindrical or a volute housing and provided with an outlet 2 in thebottom thereof and provided also with an inner ,casing 3 extendingthrough the upper portion of casing I and projecting downwardly insidesaid casing forming a closed circuit separating chamber 4 between theinside of the outer casing l and the outside of the inner casing 3.Inner casing 3 is desirable and it improves the separation but it is notessential. 6 is an opening through which steam is admitted into theseparating chamber 4. Thus far the Construction is conventional andwellknown in the art; It is reaclily seen that a cylindrical (or volute)form for separating chamber 4 will provide a steam flow path having arapidly changing direction and in a closed circuit. However, similarresults may be obtained by a guided change in direction, of at least thedry portion of the fluid, without its actually making a complete circle.

Extending from opening 6 and positioned radially to the chamber 4 is anozzle l, the exact nature of which is hereinafter defined, for con'-ducting the steam to be dried from a duct member 8 into chamber 4. WhileI have shown the outlet of the nozzle 'l positioned flush with the innersurface of the outer casing ofthe separating chamber it is to beunderstood that this exact position is not essential and that nozzle 'Imay project somewhat into the chamber 4', or may be entirely withinchamber 4 and that'the nozzle may be integral with casing l orconstituted therein as in Fig. 3 in which IA is the outer casing and 'IAand TB represent a multiplicity of nozzles receiving wet steam from theduct BA.

steam driers may be used under conditions Where the pressure andvelocity of the steam in duct 8 and the pressure and velocity of thesteam as it leaves duct 3 and the pressure and velocity of the moistureand steam, if any, leaving the opening 2 are determined by Operatingconditions in the system with which the drier' is used and cannot bemodified for the purpose of obtaining better operation in the drieritself. At the same time if the drier be of sufficient size so that thepressure drop through the drier itself remains within allowable limitsthen the velocity of the steam within the chamber 4 may not' besufiiciently high to produce as high a degree of separation as may bedesired.

The trend in modern steam' turbine' plants is toward higher steampressures and plants operating well up-toward the' critical pressure arein contemplation. As the pressure increases the difference in densitybetween the steam and water decreases until at critical pressure theyare alike and consequently the separating efiect, due to the centrifugalforce at any given velocity, becomes increasingly less as thesteampressure is increased and it is therefore apparent that it may be'highly desirable to greatly increase the velocity in chamber 4 and it isthe purpose of nozzle 1 to produce this increased ve ocity quiteindependently of velocity conditions outside the drier and to somedegree independently of the area within the separating sections oi thedrier.

When the drier is dimensioned so that the area of the internal partssuch as chamber 4 control the'velocity, the velocity must necessarily becomparatively low in order that the friction losses will not beexcessive. The velocity may however be increased several times by theuse of a nozzle or orifice actually converting pressure energy intovelocity energy which is the function of nozzle 'l in my'arrangement.Nozzle 'l converting pressure energy into velocity energy increases thevelocity in. chamber 4 to several times what it Would be if the energyConversion nozzle or orifice were not used. This means in turn that someportion of the steam entering chamber 4 from duct 8 might make severalcomplete circuits around chamber 4 before leaving the drier. Since thecentrifugal separating effect increases substantially as the third powerof the velocity any increase in velocity greatly facilitates theseparating process. i i i The purpose of nozzle 1 is to convert aportion 4 a velocity energy and is therefore converted frofn one' formof energy to another, The sides of the nozzle or orifice are carefullyproportioned so that they occupy the' optimum'position in the steam pathand are not so close to the edge of the steam path as to cause sWirls orrotary i motion in the steam path itself due to excessive contact withthe edge of the path nor so far apart as to produce space into which thesteam path' will expand and cause regeneration of the 'velocity topressure. It is thus seen that nozzle 'l must have a very specificdesign and that a slight Variation therefrom may render a nozzle uselessfor its purpose, as would be a difiser type nozzle, or ineficient aswould be a straight orifice.

i vNozzle, 'I is the same type of nozzle used in impulse turbines and isused for the same purpose, namely, for converting pressure energy energyback to' its original form, that isfrom into velocity energy and theprinciples involved '40 in the designvare well-known in the steamturbine design art and complete specifications and formulae are to befound in modern textbooks on steam turbine design and it is thought tob'e both unnecessary and undesirabletoattempt to i i incorporate thishighly technical and cumbersome detail data herein. I'

In operation the steam' to be dried passes from duet 8 through nozzle 1into 'the separating chamber 4 around which it travels at eX- tremelyhigh velocity which results in'substantially all the moisture beingthrown out against theinner wall of casing I and it then owsdownwardlyand finds its way out through outlet 2 while the dry steam is forcedinwardly toward the casing 3 and flows around the lower edge thereof andup through the central passage and thence out through opening 9. Thepurpose of dam 5 is to allow an accumulation of water or at least anaccumulation of a dense mixture of steam and water to accumulate. asshown at 20 in Fig. 6, prior to fiowing over the dam. This miXture gives'a solid body to which rotary motion 'is imparted by the velocity energyor kinetic energy from the nozzle in much the same r manner that rotarymotion or power is imparted to the wheel of an impulse turbine. In bothcases the velocity energy in the steam jet as produced by nozzle 'I isimpinging or striking a solid non-porous surface and this process ismore efficient than would be a process whereby the steam jet were.striking an elastic fluid such as steam or gas. Therefore, theConversion of velocity energy into rotary motion in' the form of power,which produces thevelocityrequiredj for separation within the Separator,is made more r tom.

of cylindrical inner casings as 3A, I3B, |3C and I3D. Each of thecasings I3A, |3B and |3C consists of an upper and lower portion, thelower portion being of greater diameter than the upper portion and thesesections are so positioned with in housing o that the smaller portion ofone is inserted inside the larger portion of the adjacent casing thespaces i4 between the telescopedportions of adjacent casings eachconstituting an independent separation chamber having its own dry steamand moisture outlets. permost casing l3A forms a chamber, I 4A, betweenitself and the housing l0 and the bottom casing, ISD, has a retractedlower portion, 23, which follows the contour of the housing ll. Each ofthe drier chambers has an individual wet steam inlet as 16 and each ofthese inlets is the termination of an individual nozzle I'l which may befed from an individual duct l8 which may be the terminal of one or moreboiler tubes. nozzle 1 of Fig. 1 and may be similarly positioned andneeds no further comment. Any number of individual units may be combinedin a common housing ll and the number in Fig. 4 has been limited to fourelements merely to limit the size of the drawing. The housing may besplit for ,assembly purposes and then joined by a weld as 2 I.

In operation the steam from duct [8 passes through nozzle l' into theseparation chamber around which it travels at high velocity causing themoisture to be thrown out against the inner wall of casing I 3A where itaccumulates until it flows over the lip or dam' !5, after which it flowsinto water space lil and eventually finds its way out through opening!2. The dry steam is forced inwardly against the outer surface of ;thesmaller portion of'casing l3B and from there flows upward into thecentral passage and thence through the upper outlet e.

A multipledrier of the type shown might be used in connection with avery high pressure boiler of the forced circulation type and in whichthe pressure is so high that there is a relatively small difference indensity between the steam and water. such a boiler might have, forinstance,

twenty-five or thirty tube circuits and the steam fiowing from thesedifferent circuits would have very difierent moisture contents varyinganywhere from a few percent to perhaps fifty percent moisture and thesmall difference in density between the steam and water means that the`steam would not separate sufi'iciently from the water, by ordinarygravity effect, as in the 'case of lower pressure boilers. Now, all 'ofthese tubes mightbe led into a common header where the steams ofvarious' qualities would, to a certain extent, become co-mingled intoone body'of steam having characteristics which would be a conglomerationof the various constituent steam .fiows but it is well known that suchmixings represent a considerable loss of power and furthermore, toobtain a complete and reliable mixing is not as simple a matter as mightat first' The nozzle ll is of the same design as' appear and 'in factmay involve rather large and unwieldly equipment. If the steam be somixed and then led through a single element drier or Separator the mostsatisfactory separation will not be obtained unless the mixture isuniform so that the moisture content of the steam entering the drierremains practically the same at all times and if the mixture is notcomplete, then there will be first a steam flow containing onepercentage of moisture and then the flow will change to one containing adifferent percentage of moisture, etc., whereas to obtain the bestOperating conditions for the Separator each individual separator shouldbe designed, particularly with respect to the nozzle, for steam having adefinite moisture content.

In my multiple type Separator each of the nozzles is designed for theparticular quality of steam which it is to handle, thus insuring thatall the fluid will be separated in the most efiicient manner regardlessof its moisture content and furthermore it is obvious that at no stageof the steam making process is it necessary to co-mingle steam flowshaving different moisture contents.

The term "impulse turbine nozzle" as used herein means a nozzle designedto convert pressure energy into Velocity energy in accordance pulseturbine design. What I claim is:

l. A multiple steam drier which includes; a'

multiplicity of cylindrical separation chambers housed in a commonpressure tight outer casing having a common dry steam passageway andoutlet for dry steam from the multiplicity of chambers and a commonpassageway and outlet for moisture from the multiplicity of chambers,each chamber having its own independent dry steam outlet to the commondry steam passageway and its own independent moisture outlet to thecommon moisture passageway and its own independent passageway forconnection to an individual source of steam to be dried.

2. A steam drier which includes; a cylindrical housing having a centralportion of uniform diameter, a lower end portion of gradually decreasingdiameter and terminating in a moisture outlet and having an upperportion of gradually decreasing diameter terminating in a dry steamoutlet; a multiplicity of cylindrical casings each having an upperportion of uniform diameter, a lower portion of uniform but greaterdiameter than the upper section and a portion of gradually changingdiameter connecting the upper and lower portions, each of themultiplicity of casings being positioned within the housing andconcentric therewith and with the smaller portion of one casingprojecting upwardly into the larger portion of the adjacent casing and'forming a separation chamber between the inner wall of the largerportion of one casing and the outer wall of the smaller portion of anadjacent casing, with a clearance space between the casings at thebottom of the chamber for the exit of moisture and a clearance spacebetween the casings at the top of the chamber for the exit of dry steam;an opening in each chamber for the admission of wet steam into thechamber and pas- 6. A steam drier' according to claim 2 characterized bythe fact that at least one of the wet steam passageways has the form ofan impulse turbine nozzle designed for wet steam having a specificmoisture content and at least one other of the wet steam passageways hasthe form of an' impulse turbine nozzle designed for wet steam having amoisture content which is dfierent from the specific moisture contentbefore mentioned; l i i '7. A steam drier which includes; an outercylindrical chamber, the central portion of which is of uniform diameterand the lower portion of which is converged to form a` cylindricalmoisture outlet of smaller diameter than the central portion and theupper portion of which is con- Verged to form a cylindrical dry steamoutlet of smaller diameter than the central portion; a cylindricaltubular member positioned in the dry steam outlet and extending downwardto approximately the point where the central portion starts to convergeinto the moisture outlet, there'- by forming a separation chamberbetween the inside of the central portion of the outer casing and theoutside of the tubular member; an opening in the separation chamber forthe admission of steam to be dried and a lip extending a short distanceinwardly from the outer casing and surrounding the lower end of thetubular member to I form a dam for assisting in retaining a film ofwater on the outside wall of the separation chamber.

e 8. A multiple steam drier. which includes; a multiplicity ofcylindrical separation chambers housed in a common pressure tight outercasing having a common dry steam passageway and outlet for dry steamfrom the multiplicity of chambers and a common passageway and outlet formoisture from the multiplicity of chambers, each chamber having its ownindependent dry steam outlet to the common dry steam passageway and itsown independent moisture outlet to the common moisture passageway andits own independent passageway for connection to sources of steam ofdiiTerent qualities to be dried.

9. A multiple steam drier which includes; a multiplicity of cylindricalseparation chambers housed in a common pressure tight outer casinghaving a common dry steam passageway and outlet for dry steam from themultiplicity of chambers and a common passageway and outlet for vmoisture from the multiplicity of chambers, each chamber having its ownindependent dry steam outlet to the common dry steam passageway and itsown independent moisture outlet to the common moisture passageway andits own independent passageway to the outside of the outer casing forthe admission of steam to be dried.

RALPI-I C. ROE.

